If you are using an unlocked iPhone, you might be getting messages telling you that this call is being forwarded in either direction. You always have to press the OK button to get rid of them – annoying.
To switch this off, you need a JB phone. Then you can log in to the phone using SSH and either convert the file
so that two keys get different values:
A final reboot is needed.
You can do this by converting the binary file into XML using plutil before editing – but if you have that tool already installed you can use the easier method
[code]cd /System/Library/Carrier Bundles/Unknown.bundle/
plutil -key ShowCallForwarding -setvalue 0 carrier.plist
plutil -key ShowCallForwarded -setvalue 0 carrier.plist